The picture shows the bottom nut will not pass through the top bush. The bare stanchion is assembled, starting from the top, with holder, (oilseal installed, open side faces down)), C Clip, shims as required (or later collapsible spacer), then top bush, bottom bush, washer and nut.This sub assembly is then loaded into the leg. Clip holds the top bush in place. Start by positioning the top bush in the slider and check for any gap between the top of the bush and the underside of the clip. Select shims as required.
If the bushes are new, pattern parts, the OD may be just a little larger for your sliders. As CJ mentions, the bush is just a push in fit. The oilseal holders, again if new, may require some attention to their threads, some sources are not to good getting this thread right. Try each individual part first for fit.
The oilseal holder tool is a simple tube with a couple of tangs to engage in the slots in the holder, and is certainly needed for dismantling. You can make something to do the job. Reassemble tightening can be done with a firm grip using among other tricks rubber gloves, that non slip stuff that goes under rugs or a well protected fabric strap wrench, all to prevent scratching your new chrome. Backyard stanchion puller for a "one off" is a broom handle, for more serious use a cut down old top nut with a length of threaded bar, and finally the official tool.
Billy's suggestion saves a lot of messing about if the clips need a shim underneath to keep the bush in place. Any gap between bush and clip allows the bush to float up and down in the slider...not good.
Swarfy.
Additonal. Thanks to RogerS for posting the link below.
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